Electric sign system



'Nov.. 12, 1940. RE":

ELECTRIC SIGN- SYSTEM Filed Feb. 23, 1938 2 Sheeis-Sheet. l

we. J

Patented Nov. 12, 1940 UITED STATES El .FFICE.

Claims.

The present invention relates to electric sign systems, and isparticularly concerned with electric signs of the type including amultiplicity of electric bulbs or glow tubes arranged in a bank 5 forthe purpose of producing or reproducing by means of light and dark glowtubes or bulbs, images, printed matter, motion pictures, or intelligentcharacters of any kind.

One of the objects of the invention is the provision of an improvedelectric system by means of which the impressions on a moving picturefilm may be reproduced in a bank of glow tubes, such as neon tubes, orby means of incandescent electric right bulbs.

Another object is the provision of an improved system of the classdescribed, in which the number of electric conductors which are requiredfor controlling the glow tubes or incandescent bulbs is greatly reduced,so that the conductor cable is relatively small and the difiiculties ofsupport and expense of such a cable are greatly simplified.

Another object of the invention is the provision of an improved systemof the class described, which is adapted to reproduce the impressions ofa moving picture film in a bank of glow tubes or incandescent bulbs,butwhich requires only a fraction of the controlling devices andconductors which are utilized in the devices of the prior art.

Other objects and advantages of the invention will be apparent from thefollowing description and the accompanying drawings, in which similarcharacters of reference indicate similar parts throughout the severalviews.

Referring to the drawings:

Fig. 1 is a schematic illustration including a wiring diagram of asystem constructed according to the present invention;

Fig. 2 is another schematic diagram showing the arrangement of thecontrolling photocells with respect to the motion picture projector, theView being taken in plan;

Fig. 3 is a diagrammatic elevational view of the same arrangement shownin plan in Fig. 2;

Fig. 4 is a fragmentary sectional view through a part of the distributoror commutator shown in diagrammatic form in Fig. 1;

Fig. 5 is a fragmentary View of a portion of a modified wiring diagramemploying incandescent electric light bulbs in addition to glow tubes;

Fig. 6 is another fragmentary illustration of a portion of a diagramwhich may be substituted for a part of Fig. 1, illustrating a modifiedform of controlling device,

The present system contemplates the use of glow tubes arranged in a bankfor reproducing the impressions of a motion picture film or glow tubesmay be used in connection with incandescent bulbs according to thecircuit of Fig. 5.

The bank of glow tubes is controlled by a series of grid controlledgaseous rectifier tubes, such as Thyratrons, which are in turncontrolled by photo-cells. The rectifier tubes are so biased that theybreak down and pass current at a certain intensity of light, and theyare biased by means of the photo-cells, the voltages of which areimpressed upon the grids of the rectifier tubes.

Such glow tubes require a higher voltage for starting the glow tube,called the flash voltage, and thereafter for steady operation the glowtubes require a lower voltage, and the present system makes provisionfor the starting and operation of the glow tubes.

Referring to Fig. 1, I0 indicates in its entirety the-complete system,which includes the motion picture projector H, suitable speed reducinggearing l2, and the distributor or commutator it,

which is driven by the speed reducing gearing in synchronism with themotion picture projector.

Referring to Fig. 3, the electric motor 9 drives the motion pictureprojector ll through the speed reduction gearing l2 at a much slowerspeed than the speed of rotation of the distributor it, as thedistributor l3 rotates once for each frame of the motion picture film inthe projector, and the motion picture film passes at a continuous ratepast the lenses of the projector.

It also includes the bank of glow tubes, such as neon tubes, thecomplete bank being indicated at M, the series of controlling Thyratronsindicated as a series by l5, and the series It of photocells, togetherwith suitable energizing circuits and devices will be described indetail hereinafter.

Referring to the motion picture projector II, this projector differsfrom the projectors of the usual type in that the film is not moved stepby step, but is moved constantly at a uniform rate of speed past thelenses. The size of the projection in the example selected mustcorrespond in width to the length of the row of photo-cells. The heightwould be equal to the width in this example, and therefore the lightfalling on the row of photo-cells is one-hundredth of the height of theprojection. The picture will constantly move in one direction, such as,for example, downward if the film is fed from the reel #8 through theprojector II through the reel l9.

Referring to Fig. 3, the projected beam I1 is shown in verticalelevation, and the depth of the beam at the point 29 need only besufficient to cover the light responsive part of the photocell I 6.

It should be understood that in Fig. 3, l6 indicates a series ofphoto-cells which are arranged one behind the other in that figure, asindicated in Fig. 1.

Referring to Fig. 2, the projection system is there shown in plan, andit will be noted that there are a multiplicity of photo-cells l6arranged in a row and embraced by the projector beam 5'! from the motionpicture projector H.

For example, in a system employing 10,000 glow tubes in the bank M, theseries of photo-cells I6 may include 100 photo-tubes in a row, as shownin Fig. 2. The disclosure of Fig. 2 with one photo-tube in one end and aplurality at the other end, is supposed to indicate an arrangement inwhich a multiplicity of photo-tubes are arranged 'in a row, such as, forexample, 100.

Referring now to Fig. 1, the bank Id of glow tubes may consist of 100horizontal rows of glow tubes, each row having 100 tubes. For example,the lowermost horizontal row is indicated by the numeral I90, the nextby the numeral If, and so on up to I 99. The individual glow tubes beingidentical, any one of them may be indicated by the numeral 2' and theremay be any predetermined number of glow tubes in one of the rows I99,such as, for example, 100 glow tubes in the example described.

It should be understood that any number of rows may be utilized and anynumber of glow tubes in a row. The bank of glow tubes, includingsuitable sockets and circuits, are all mounted upon suitable frameworkand maybe located in any desirable place where an electric sign would belocated.

In order to secure uniform light distribution the 10,000 glow tube bankdescribed would be arranged with equal spacing forming a square bank, tobe used with a film having a square frame. For a rectangular frame inwhich the horizontal dimension is longest, as is usual in motion picturefilms, the shape of the bank would be similar to the film frame, and thenumber of lamps in any row proportional to the corresponding dimensionof the frame.

It will be observed that there are a number of conductors 2l25 extendinghorizontally in the diagram, comprising one conductor for each row ofglow tubes, and these conductors each have leads 26 extending downwardin the diagram and connected to one of the electrodes 2'! of the glowtubes in the corresponding row.

The diagram also has a number of additional conductors Eli-33, etc. (100conductors in all) extending vertically on the diagram, and eachconductor having a multiplicity of leads '34, which extend horizontallyon the diagram and are connected to the other electrode 35 of thecorresponding glow tubes in the vertical row. Thus the glow tubes mayall be energized by the energization of appropriate conductors, such as,for example, the glow tube H00 is energized through the conductors 33and 2!.

The distributor It may comprise a cylindrical member which is providedwith a cylindrical body 36, carrying a cylindrical strip contact 31 thatcovers the major portion of the periphery of thecylinder 36. The shortstrip 38' is of insulation,

and the member 39 is a very short contact. The relatively short strip 49is another strip of insulation, and the contact 31 extends from thepoint 4! around to the point 42.

The cylinder 36 is mounted for rotation about the axis 43, and it isactuated by the same electric motor which drives the motion pictureprojector I l, but it is driven through the speed changing gears l2 insuch manner that it is synchronized with the film. For example, when thefilm moves at a rate of twenty frames per second, the distributor mayrotate clockwise at 20 revolutions per second; that is, the distributorwill make one revolution in 0.05 second.

The distributor is provided with a plurality of brushes 5l-56, etc. (100brushes in all for 100 rows of lights), and each of the brushes isconnected to one of the horizontal conductors 2 l-2 5, which leads tothe electrodes of one of the horizontal rows of glow tubes.

Referring to Fig. 4, this is a diagrammatic fragmentary illustration ofpart of the distributor, shown in section with one brush 56, forexample, engaging the insulating segment 49.

The contact member 39 is connected by a conductor 51 to the innerslip-ring 58, and the contact member 31 is connected to the outerslip-ring 59. A brush 66, engaging the outer slip-ring 59, is connectedby conductor 6| to ground at 62 and brush 63, engaging the innerslip-ring, is connected by conductor 61:, to the negative side of thenegative terminal 65 of a direct current source of supply 66, such as arectifier and filter without a ground, which is energized by thesecondary 61 of thetransformer 68, the primary being indicated by thenumeral 69.

The transformer 68 may be connected to the ordinary 60 cycle 110 voltlighting power supply. The glow tubes in the bank I4 are adapted to becontrolled by a plurality of Thyratrons IO-l5, etc. (100 in all), oneThyratron being required for each of the 100 vertical rows of glowtubes.

The grid 16 of each Thyratron is connected by a conductor 11 to oneelectrode 18 of a photoelectric cell 19. The grid is also connected bythe same conductor Tl to a bias resistor 80, which is connected byconductor 8! to ground. The other electrode 8| of the photoelectric cell79 is conducted by conductor 82 to a common conductor 83, leading to thepositive terminal 84 of the power supply 66.

The plate 85 of each Thyratron is connected to the positive conductor86. The filament 81 of each 'Ihyratron is provided with a suitablesource of energization comprising a separate transformer 229 for eachtube, only one being shown, due to lack of space. In addition, filament8'! is connected by the conductor 88 to one of the conductors 2833. Theleads 2933 from one of the electrodes of each of the glow tubes in thebank l4 are each connected to surge resistors 89, which have theiropposite ends connected to ground at 90, and the conductors 2833 arealso each connected at 9| to one terminal of a reactor 92.

The opposite terminal from each of the reactors is connected to a commonlead 93, which extends to the positive side of a source of directcurrent of suitable voltage for maintaining the glow tubes M in aglowing condition after they have once been started.

The negative terminal of this direct current source of supply isindicated by the lines 94, 95, connected to ground at 96.

Referring again to Fig. 1, it will be observed that the glow tubes areadapted to be energized by direct current from the source 94, 95, andthe circuit may be traced as follows: 94, 93, '92, 9|, 33, 34, 35, 21,26, 2i, 5|, 3?, 59, 6!), 6!, to ground at 62, ground at 96, and negativeterminal at 95. This energization takes place, however, only when thebrush El is in contact with the contact 31, which covers the majorportion of the periphery of the cylinder 36.

It should also be understood that there are 100 of the brushes likebrush 5!, and they are disposed much more closely together than isindicated on the diagram of the distributor. The glow tubes in the bankM are also adapted to be energized at a predetermined time by directcurrent of a higher voltage; that is, the starting or flashing voltagewhen the brush is in contact with the relatively narrow contact 39,.andthe circuit may be traced as follows: From the negative terminal 65 ofthe source of supply 56, through conductor E l, brush (it, slip-ring 58,conductor 5?, contact 39, brush 5|, conductor 2i, 25, electrode 27, glowtube till], electrode 35, conductor 3 38, conductor 88, to filament 81of the Thyratron Ill to plate 85, conductor 85, and positive terminal84.

Referring to Fig. 4, the operation of the distributor is as follows:When, for example, the brush 56 is engaging the insulation 38, thecorresponding row of glow tubes in the bank It are de-energized becausethe circuit is broken at the insulation 38. The horizontal width of theinsulation segment 38, that is, the peripheral width in Fig. 4, issuliicient so that the lapse of time during which the brush 56 engagesthis insulation and does not engage either contacts '3! or 39, isgreater than the time required for de-ionization of the particular glowtube and gaseous rectifier tube 1GT5, etc. The data supplied for glowtubes usually includes the time required for dye-ionization, andtherefore the segment 38 of the distributor may be designed accordingly,taking into consideration the speed at which the distributor I3 rotates.56 and the contact 39 is such that there will be contact for asufiicient length of timeto eiiect a flash-over of the corresponding rowof glow tubes in order to start the glowing of the tubes.

That is, the time of contact between brush 5% and contact 39, must beequal to, and is preferably slightly more than, the time required forionization of the glow tube.

The distributor rotates to the right in Fig. l, and after the brush 55engages the contact 38, the insulation segment passes under the brush 56and separates the contact 3'! from the contact 39. There is a period oftime which is represented by the space indicated between the arrows 91,98, during which the glow tube is entirely disconnected from the contact39 or the contact 3?, but this period of time may be made smaller thanthe de-ionization period of the glow tube, so that thereafter the brush56 will be engaged by the contact 31, while the corresponding glow tubesare still ionized. The row of glow tubes to which the brush 56 isconnected will, therefore, be continuously energized by the cylindricalcontact 3'5 until the brush again reaches the point fill rides over theinsulation segment 38.

It will thus be observed that the distributor is adapted to light, bymeans of a flash voltage, each row of glow tubes in the bank it at apredetermined time, and thereafter disconnect the flash voltage andapply a steady direct current The width of the brushes voltage of lowerpredetermined value for maintaining the energization of the glow tubesthroughout one revolution of the distributor.

The direct current source 9 5, 95 of voltage for maintenance of the glowtubes in the row is always available and connected whether it is used ornot, but such maintenance voltage 9 95 is not adapted to light the glowtubes of any particular row until they have first been energized by theflash-over voltage which is provided through the contact 39. Thisflashover voltage is only provided when the corresponding Thyratronlil15, etc. breaks down and permits direct current to flow.

Each Thyratron is controlled by a photoelectric cell. The grids of theThyratrons are connected through ground and through the grid resistorsto the negative potential of the second source of direct current supply,that is, M, 95, and therefore the grid resistors will tend to keep thegrids at negative potential. The grid resistance is so designed that theThyratron tubes or rectifiers will be in condition to pass current at adesired intensity of'photo cell'illumination, but will not pass anycurrent below this value of illumination. The photo cell acts like avariable resistance, and light impinging upon it decreases itsresistance. As the photo cell is connected to a positive source byconductor 83, grid 26 will tend to become positive as light on the photocell increases, and the rectifier tube breaks down and passes current tothe glow tubes at a certain grid potential. Thus a motion picture filmwhich has light portions and dark portions will be treated as though thelighter portions are entirely light and of the same shade, and thedarker portions are all entirely dark and of the same shade.

As previously stated, the motion picture projector projectsone-hundredth the light of the frame of the film on the row lb ofphotoelectric cells.

The distributor l 3 moves synchronously with the motion pictureprojector, and each brush 5l--55 or row of glow tubes loll 899'corresponds to a particular part of the film picture of one frame, andeach brush and row of glow tubes is appropriately connected in circuitat the proper time, corresponding to the location of its portion of thefilm opposite the projection slit. For example, if the film speed is '26frames per second, the distributor rotation may also be in a clockwisedirection at 20 revolutions per second, or one revolution in 0.05second. Since there are 100 brushes, each brush will, therefore, have atime width of not more than 0.0005 second, and this width will bedecreased as the brush spacing is increased.

The glow tubes of the bank 24 each correspond to a small section of thearea of the film, which section is one-hundredthas long andone-hundredth as wide as the complete frame, and each glow tube will bemade light or dark, corresponding to the presence of light or dark onthat relatively small section of the film which corresponds to the glowtube in question.

. In brief, the picture of the motion picture film will be reproduced onthe bank of lights I l, except that there will be no shading of the glowtubes, and each glow tube will be entirely light or entirely dark. Theresulting picture in the bank of glow tubes corresponds to a black andwhite picture without any intermediate shades. The surge resistors 38serve to absorb any inductive surges from the reactors 92 whenever thereis a sudden drop of current through the rein circuit,

actors due to the extinguishment of a large number of glow tubes. Thereactors 92 serve to cause each of the vertical rows of glow tubes tooperate separately in so far as their control by the Thyratrons isconcerned.

The direct current voltage supplied by the Thyratrons is in the form ofa high frequency impulse, and since all of the conductors 28-33 areconnected to a common conductor 93, one Thyratron would otherwise applyvoltage to all of the glow tubes simultaneously through the conductor93, were it not for the reactors 92, which prevent the direct currentimpulses of high frequencies from the Thyratrons from going down intothe conductor 93 and up into other rows of glow tubes.

Referring to Fig. 6, rectifier tubes might be substituted for thereactors and surge resistors, and I prefer to use rectifier tubes of theIgnitron type. The leads from these Ignitron rectifiers correspond tothe leads from the reactors 92 so that the fragmentary diagram of Fig. 6may be substituted for a portion of Fig. 1. 2|!) indicates the Ignitronwhich is a mercury vapor rectifier tube, having mercury at 2, acarborundum igniter electrode 2I2, and another electrode 2H3. Lead 2Mextends from 212 to copper oxide rectifier discs H5, and lead 2H6extends from the latter to 93.

The rectifier tubes merely serve to permit direct current to passthrough them only in one direction from the positive terminal 94 to theglow tubes, but do not permit direct current impulses from theThyratrons to pass in the reverse direction. Thus they serve the samepurpose as the reactors 92 in causing the vertical rows of glow tubes tobe controlled separately by corresponding Thyratrons.

Referring to Fig. 5, this diagram shows a portion of a bank of glowtubes and incandescent bulbs in which the circuits are substantially thesame as those of Fig. 1, except that each glow tube 20 has in the samecircuit, in series with it, an incandescent bulb 200.

The glow tubes are only one-tenth as efficient, in so far as productionof light is concerned, as incandescent bulbs, and the glow tubes mayserve as relays for controlling the energization of incandescent bulbs.

The incandescent bulb and glow tube are balanced as to resistance andcurrent so that the incandescent bulb is fully lighted when sufficientcurrent passes through the glow tube to energize the glow tube. Theinclusion of the incandescent bulb in series with the glow tube does notinterfere with the flash-over or ionization of the glow tube because thefull voltage is initially applied to the glow tube at the beginning.

In this case the bank will include not only the glow tubes, but thebrighter incandescent bulbs controlled by the glow tubes, and a muchbrighter light and dark picture representation may be secured by the useof incandescent bulbs.

It will thus be observed that the system is adapted to scan the film andprovide for the individual control of the glow tubes, each tube beinglight or dark in accordance with its corresponding area on the frame ofthe film. The space between the brushes 97 and 5| at the bottom of thedistributor in Fig. 1 corresponds to the transition from one frame tothe next frame. This space is made slightly larger than the other brushspaces, in the event there are spaces between the frames of the film.

It will thus be observed that only 100 photoelectric cells and 100Thyratrons are required to control the lighting of 10,000 glow tubes,and instead of requiring 10,000 conductors extending from the electricsign or bank of glow tubes to the controls, it is only necessary to have201 conductors, comprising the conductors 2l-25, conductors 88 andconductor 93 extending downward from the electric sign to the controlapparatus.

The present system is, therefore, adapted to simplify the connection andcontrol of such electric signs, and systems constructed according to thepresent invention may be constructed at a much lower cost. Whereas thesize of electric signs would probably be limited by the size or weightof the cable containing the insulated conductors leading to the glowtubes or incandescent lamps if the conductor were used for each tube orlamp. In the present invention the size of the cable is greatly reducedand does not substantially limit the number of lamps that may be used.

Only one-fiftieth as many conductors leading to the sign are requiredaccording to the present invention as would be required if a conductorwere necessary for each separate tube. The reduction in the number ofphoto cells and Thyratrons also effects a substantial saving in expenseof installation because such special tubes are still available only at asubstantial cost.

It will thus be observed that I have invented an improved electric signsystem by means of which the pictures on a photographic motion picturefilm or any other film may be reproduced on an electric sign, comprisingglow tubes and/or incandescent bulbs.

Such electric signs are highly desirable for advertising because of thepictures or disclosure of the electric sign which may be constantlychanging and may thus constantly attract the attention of observerswithin sight of the electric sign. Whereas ordinary motion pictureswould hardly be visible, an electric sign in which the picture isreproduced in dark or light on glow tubes or incandescent bulbs isvisible at a great distance and either in the night time or in thedaylight.

While I have illustrated a preferred embodiment of my invention, manymodifications may be made without departing from the spirit of theinvention, and I do not wish to be limited to the precise details ofconstruction set forth, but desire to avail myself of all changes withinthe scope of the appended claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States, is:

1. In an electric sign system, the combination of a motion pictureprojector adapted to move its film at a continuous and uniform speedwith a distributor synchronously driven with said projector, saiddistributor rotating once for each frame of a film carried by saidprojector, a series of light responsive cells arranged in a rowtransversely to the direction of movement of the film to have atransverse element of the picture from said film projected on saidcells, a series of gridcontrolled gaseous rectifier tubes, including onegrid-controlled tube for each of said cells, said cells controlling theoperation of said grid-controlled tubes, a bank of glow tubes adapted tore-- produce in lighted and dark tubes the light and dark parts of thesubject-matter of said film, said glow tubes being arranged in primaryand secondary rows of glow tubes, said primary rows being transverse tosaid secondary rows, one terminal of the glow tubes in each of saidprimary rows being connected to the .plate' circuit of one of saidgrid-controlled tubes to be controlled separately by saidgrid-controlled tubes, said glow tubes also having their other terminalsconnected in multiple to provide secondary rows of glow tubes, theterminals of each secondary row being connected to one of a plurality offixed contacts engaged by said distributor, said distributor having aconducting segment extending over the major portion of its peripheryiior energizing said glow tubes during a corresponding part of eachrotation of the distributor, a source of energization for the conductingsegment adapted to maintain illumination 'of said glow tubes, the endsof said segment being separated by a deionizing insulating segment andenergized flash-over segment connected in the plate circuit of saidgridcontrolled tubes, and another insulating segment of greater widththan said fixed contacts, a source of energization for said flash-oversegment adapted to eiiect initial ionization of said glow tubes, andenergizing circuits for said glow tubes, gridcontrolled tubes, andcells, whereby the light responsive cells effect a break-down of theplate circuits of said. grid-controlled tubes selectively depending onpredetermined lightness or darkness of parts of the film and the glowtubes are ignited and maintained energized or kept dark depending on thelightness or darkness of the corresponding parts of the film, the saiddistributor deionizing each energized glow tube once during eachrotation of the distributor whereby the rows of glow tubes connected tosaid fixed contacts are successively energized in correspondence withtransverse linear elements of the subj ect-matter on the film, and aremaintained energized throughout the passage of one frame of the film.

2. An electric sign system according to claim 1,

the said deionizing segment being of suflicient width relative to thespeed of rotation of the distributor to break the circuit of the glowtubes over a period of time greater than the deionization period of theglow tubes.

3. In an electric sign system, the combination of a motion pictureprojector adapted to move its film at a continuous and uniform speedwith a distributor synchronously driven with said projector, saiddistributor rotating once for each frame of a film carried by saidprojector, a series of light responsive cells arranged in a rowtransversely to the direction of movement of the film to have atransverse element of the picture from said film projected on saidcells, a series of gridcontrolled gaseous rectifier tubes, including onegrid-controlled tube for each of said cells, said cells controlling theoperation of said grid-controlled tubes, a bank of glow tubes adapted toreproduce in lighted and dark tubes the light and dark parts of thesubject-matter of said film, said glow tubes being arranged in primaryand secondary rows of glow tubes, said primary rows being transverse tosaid secondary rows, one terminal of the glow tubes in each of saidprimary tion for the conducting segment adapted to maintain illuminationof said glow tubes, the ends of said segment being separated by adeionizing insulating segment and energized flash-over seg-' mentconnected in the plate circuit of said gridcontrolled tubes, and anotherinsulating segment of greater width than said fixed contacts, a sourceof energization for said flash-over segment adapted to efiect initialionization of said glow tubes, and energizing circuits for said glowtubes, gridcontrolled tubes, and cells, whereby the light responsivecells effect a break-down of the plate circuits of said grid-controlledtubes selectively depending on predetermined lightness or darkness ofparts of the film-and the glow tubes are ignited and maintainedenergized or kept dark depending on the lightness or darkness of thecorresponding parts of the film, the said distributor deionizing eachenergized glow tube once during each rotation of the distributor wherebythe rows of glow tubes connected to said fixed contacts are successivelyenergized in correspondence with transverse linear elements of thesubject-matter on the film, and are maintained energized throughout thepassage of one frame of the film, the said deionizing segment being ofsufficient width relative to the speed of rotation of the distributor tobreak the circuit of the glow tubes over a period of time greater thanthe deionization period of the glow tubes, and the said energizingcircuits of said glow tubes including a reactor for each of the primaryrows of said glow tubes controlled by each grid-controlled tube to causeeach primary row of glow tubes to operate separately when controlled bysaid grid-controlled tubes, although energized from a common conductor.

4. An electric sign system according to claim 3, and a surge resistorfor each of said reactors to absorb inductive surges from the reactorsdue to the extinguishment of a large number of glow tubessimultaneously.

5. An electric sign system according to claim 1, and an incandescentlamp connected in series with each of said glow tubes and adapted to beenergized when the corresponding glow tube is ignited, the current ofeach glow tube corresponding substantially to that of each lamp.

JOHN A. REID.

